???? PROJECT SUMMARY / ABSTRACT ??????????????????????????????????????????????????????? Alcohol abuse disorders (AUD) are a major health hazard that affects millions of people every year in the United States. Repeat alcohol exposure can lead to tolerance, increased preference and consumption. Such behavioral changes, and the accompanying neuronal plasticity, underlie addiction, yet many molecular mechanisms governing these changes remain to be elucidated. Signaling through the insulin receptor (InR) in neurons is known to modify plasticity, but its effects on alcohol-induced behavioral responses are not known. Our goal is to understand the cellular, neural, and circuit mechanisms of Arf6-dependent nervous system InR signaling in alcohol-induced plasticity. This is based on our published data that Arf6 mediates InR signaling in vivo and in cell culture. First, we will determine the mechanisms of Arf6-mediated InR signaling and endocytosis. We will systematically, and comprehensively test the role of two gene families known to directly regulate the function of Arf6. Second, we will determine neural circuits that specifically affect ethanol-induced tolerance and consumption preference, as well as the nave aversive reactions to alcohol. We will test the role of Arf6 regulators in these circuits in alcohol-induced behavioral responses. Third, we will determine in vivo mechanisms how signaling from the InR pathway can affect distinct alcohol-induced behavioral changes: tolerance, and consumption preference. The genes we propose to investigate are all conserved from Drosophila to humans, and the proposed research will advance our molecular understanding of the mechanisms regulating alcohol-induced behavioral changes. This in turn, will result in the identification of new risk factors and therapeutic targets for the treatment of alcohol abuse disorders.